Incoming DUP leader Sir Jeffrey Donaldson has warned the Irish Government to stop “cheerleading” for the Northern Ireland Protocol.Sir Jeffrey, who became leader-designate on Saturday, signalled that north-south relationships will be impacted if Irish ministers do not change stance.He accused the administration in Dublin of only advocating for the nationalist side of the community in Northern Ireland and ignoring the concerns unionists have over the imposition of Irish Sea trade barriers under the terms of the Brexit Withdrawal Agreement.After his leadership bid received the endorsement of the DUP electoral college on Saturday, Sir Jeffrey was asked about engagement with the Irish Government going forward.